a(n) = j if n = [ j*sqrt(3) ], else a(n) = k if n = [ (k/2)*(3 + sqrt(3)) ].

Terms

a(0) =1a(1) =1a(2) =2a(3) =2a(4) =3a(5) =4a(6) =3a(7) =5a(8) =4a(9) =6a(10) =5a(11) =7a(12) =8a(13) =6a(14) =9a(15) =7a(16) =10a(17) =8a(18) =11a(19) =12a(20) =9a(21) =13a(22) =10a(23) =14a(24) =15a(25) =11a(26) =16a(27) =12a(28) =17a(29) =13